public abstract class Duck {
    String name;
    FlyBehavior flyBehavior;

    public Duck(String name) {
        this.name = name;
    }

    public void setFlyBehavior(FlyBehavior flyBehavior) {
        this.flyBehavior = flyBehavior;
    }

    public void yell(){
        System.out.println("嘎嘎叫");
    }
    public abstract void fly();
}
